Improvement in machines for rolling screw-threads on bolts anetrods



T. T. PROSSER MACHINE EoR ROLLING SCREW THREADS oN BoLTs AND RoDs.

NAO. 181,010. Patented Aug.15,1876.

'liTNITEnfy STATES PATENT OEFIGE.

TREAT 'I'. PROSSER, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN MACHINES FOR ROLLING SCREW-THREADS 0N BOLTS ANU RODS.

Specification forming part of Letters Patent No. 181,010, dated August 15, 1876; application tiled December 30, 1875.

-for such an adjustability of the rolls that their Obliquity with'reference to each other can be changed to regulate. the pitch of the screw-thread formed on a bolt or rod passed through between them second, in arranging the shafts of the rolls side by side, and in such a manner'that their axes will converge when in position for Work in the direction in which the rolls feed, so that the threaded surfaces of the rolls willstand at a slight angle and operate gradually in rolling a screw-thread on a bolt or rod, aud facilitate the feeding thereof third,of certain novel details of construction,` so fully explained in the following general description, and so specifically pointed out by the claims, that a detailed statement thereof at this point would be superfluous.

In the annexed drawings, Figure lis a sectional elevation of a machine that illustrates my improvements.l Fig. 2 is a horizontal section of the same. Figs. 3, 4, and 5 are detail views, hereinafter more particularly referred to.

The same letters of reference are used in all the figures in the' designationof identical parts. i

Most of the working partsof the machine shown are arranged in a cylindrical casing, A, supported on a stand or column, A1. The rear head A2' of the casing has an elongated central hub to afford an extended bearing' forl the driving-shaft B, which carries va fast and a loose pulley on its overhuu g end outside of the casing. The other end of the sha-ft as a bearing in the central hub ofpa cross-b C,

(best seen in Fig. 4,) which has lsegmental au ges ttin g the bore of the cylindrical casin g, within which it is suitably fixed by set-screws c. The driving-shaft is tubular from, end to end, and a hole is also formed in the center of bar C, in line with and of the same size as the hole of shaft B. The teeth' of a gear-wheel, B1, cuton the driving-shaft, or of a separate gear-Wheel ixed thereon, mesh into the gearwheels D2 and E2 on the shafts l)l and El, located on opposite sides of the driving-shaft within the casing, and drive these shafts in the same direction and at the same velocity.

'lhe threading-rolls D and E are fixed, respectively, to the shafts Dl and El, just outside of the cross-bar C. The peripheral surface of each rollhas a number of annular threads formed upon it, as best seen in Fig. 5, the threads heilig the counterpart iucrosssection of the grooves to be rolled ou the bolts or rods, in order to'form the desired `screw-thread thereon'.`

`A The shafts of the threading-rolls turn-iu globe-like boxes F and F7, giving support to them at both ends. The boxes F are snugly fitted in recesses in a disk, G, and are covered by retaining-plates g. The disk Gis loosely mounted ou the driving-shaft B within the casing, between the head A2 of which and a pollar on the shaft it is suitably confined. It has tieth g on a portion of its periphery, to mesh into a pinion, H, by means 'of which it may be turned on the driving-shaft to some extent. The pinion H is fixedl on a short spindle, h, which turns in a bearing in the head A2, and is provided with a milled/head or button, H', for Nturning it. A clampingscrew, G', enters a tap in the disk G through a sectoral' slot, a, (best seen in dotted lines in Fig..3,) in the head A2, and is used to fix the disk after it has been properly adjusted by the pinion. A

The boxes F are fitted in an extended horizontal recess in the fixed front head A? of the casing, so'that they can be moved horiz/oni tally only.

The shafts Dl and E1 are so arranged by the proper adjustment of disk G that the threading-rolls turn in different but intersecting planes, as shown in Fig. 2r Thev pitch of the thread formed by the action of the rolls depends upon their relative Obliquity, which are also suitably formed, so as to adapt them to rotate the shafts with equal smoothness in any position that they may assume. In the machine illustrated, the range of adjustment of diskG is so great that the inclination of the threading-disks can be 'entirely reversed,

lso that they can be arranged to feed in the direction ot' the arrow in Fig. 1, whether the driving-shaft turns in one direction or the other. The boxes F can be adjusted laterally in the head A3. As shown in Fig. 2, they are separated as far as the length of the recess in head A admits, and the vertical planes of the axes of the threading-rolls are about parallel. The threading-rolls are now so far apart as to freely admit between them the largest-sized bolt or rod the machine is'designed to operate on, so that the rolls must be moved toward each other to make an impression on such a rod or bolt.

When the rolls are thus moved toward each other their shafts will assume a converging position, in consequence of which the threaded surfaces of the rolls will be at a slight angle at the bite, so that their threads will gradually operate. This converging disposition of the surfaces of the rolls at th-e bite has also a tendency to facilitate the feeding of the bolt or rod subjected to their action. The threading-rolls operate between the cross-bar C and the tubular bridge-piece or guide I, so that the'bolt or rod will have a support on both sides of the rolls. The bexes F are adjusted by right and left screw-spindles K K, turning in taps in the head A?. Each of these screwspindles carries a fixed pinion, K', engaging rack-teeth on a yoke, L. The stems L of these yokesgwill be rigidly connected by a cross-bar, and a treadle or similar device provided for giving a vertical motion to the racks, by which the screw-spindles may be simultaneously made to force the threading-rollswith equal .force against the bolt or rod to be threaded. The front he'ad A3 of the machine has a central aperture for the introduction and discharge of the bolts or rods.

Long rods may be fed tothe threadingrolls through the hollow driving-shaft.

The casing A is closed Water-tight at both ends by its heads, so that it can be filled with water, oil, or the like up to the aperture in its front headffor the twofold purpose of lubrication and, keeping the vthreading-rolls cool, the latter of which is of special importance when the bolts or rods are heated before they are fed to the rolls. The tight casingalso serves to protect nearly all the principal working parts of the machine.

What I claim as my invention, and desire te secure by Letters Patent, is-

1. In a machine for forming screw-threads on bolts and rods by cross-rolling, the colnbination,7 substantially as specified, of the threading-rolls, their shafts, and means for adjustingxthe shafts to change the relative Obliquity of the threading-rolls, and thereby regulate the pitch of the thread to be formed.

2. In a nia-chine for forming screw-threads on bolts and rods by crossrolling, the peripheral threading-rolls carried on shafts which have a converging position when the rolls are at work, so that the several threads upon the rolls shall successively increase the depth of cut, substantially as and for the purpose specified.

3. In a machine for forming screw-threads on bolts and rods by cross-rolling, the combination, substantially as specified, of the shafts shaft, arranged centrally between them, and the intermediate gear-wheels.

4. In a machine for forming screw-threads on bolts and rods by cross-rolling, the combination, substantially as specified, of the threading-rolls, their shafts, the globe-like journalboxes, and the circularly-adjustable disk, carturn at one end.

5. The combination, substantially as speciglobe like journal boxes, the centrally arranged driving-shaft, the gear-wheels for rotating the threadingrolls, and the circularlyadjustable disk, carrying the journal-boxes, in which the roll-shaft Jrn at one end.

6. The combination, substantially as specified, of the threading-rolls, their shafts, the right and left screw-spindles', and the`racks and pinions for simultaneously turning said spindles, to force the threading-rolls toward each other.

7. The combination, substantially as specified, of the tubular driving-shaft, the crossbar aftbrding a bearing for the inner end of said shaft, the guide in front of the said crossbar, and the threading-rolls.

8. In a machinefr forming'screw-threads on bolts and rods by cross-rolling,-the supporting-frame, having the form of a hollow cylinder, closed by heads at both ends, so as to form a reservoir for water, oil, or other substances used for lubricating and cooling purposes, as well as a protecting-cover for all the principal working parts of the machine.

In testimony whereof I have signed my name to the foregoing `specification in the presence of two subscribing witnesses.

TREAT T. PROSSER.

L. L. WILSON.

of the threading-rolls, the tubular drivingryingthejournal-boxes,in which the said shafts fied, of the threading-rolls, their shafts, the` 

